STROKE


DEFINITION

  • Cerebrovascular accident or stroke is defined as acute onset of neurological disorder of vascular etiology.
  • Stroke may be-
  1. Hemorrhagic 
  2. Ischemic.
  3. TYPES OF HAEMORRHAGIC STROKE.
  1. Primary intracerebral stroke.
  2. Subarachnoid hemorrhage.
  3. Primary intraventricular hemorrhage.
  4. TYPES OF ISCHAEMIC STROKE.
  1. Transient ischemic attack.
  2. Reversible ischemic neurological deficit.
  3. Complete stroke.
  4. Lacunar infarcts.
  5. Multifocal small infarcts leading to multi-infarct dementia.

PATHOPHYSIOLOGY

  • The 2 main advances in stroke are delineation of ischemic penumbra in ischemic stroke and observation of hematoma growth.

ISCHAEMIC STROKE

  • Severity of stroke related to degree of impairment of cerebral blood flow and the time to reperfusion. When blood flow is less than 10ml/100g/minute-neuronal cells die.
  • Ischemic penumbra: Is a zone of moderately reduced cerebral blood flow between the ischemic core and the normally perfused brain.
  • Within ischemic penumbra, neurons are hypoxic, functionally inactive but still viable. Brain tissue undergo necrosis due to perfusion failure and leads to secondary biochemical events like release of glutamate, influx of Na+ and Ca+ into cells, release of free-radicle species.

INTRACEREBRAL HAEMORRHAGE

  • I.C.H is a dynamic process and substantial hematoma growth can occur in first 3 hour with most of growth in first 1 hour. Expansion is due to bleeding and rebleeding.
  • Hemostatic therapy in I.C.H would reduce volume of hematoma and result improved outcome.

RISK FACTORS 

  1. HIGH RISK
  2. Hypertension.
  3. Diabetes mellitus.
  4. Atrial fibrillation with or without valvular heart disease.
  5. Smoking.
  6. Vasculitis.

B.    LOW RISK.

  1. Migraine.
  2. Oral contraceptives
  3. Alcohol.
  4. Patent foramen ovale.
  5. ADDITIONAL RISK FACTOR IN YOUNG.
  6. Protein c and s deficiencies.
  7. Anti thrombin deficiency.
  8. Antiphospholipid syndrome.
  9. Sickle cell anemia.
  10. Thrombotic thrombocytopenic purpura.
  11. TRANSIENT ISCHAEMIC ATTACK
  12. Abrupt onset focal neurological deficit of presumed vascular etiology not lasting more than 24 hrs.
  13. Most episode lasts for seconds to minutes.
  14. More recent definition of T.I.A is a brief episode of neurological dysfunction caused by focal brain or retinal ischemia with clinical symptoms lasting less than one hour and without evidence of acute infarction.

MECHANISM

  • Atherosclerotic plaque.
  • Platelet thrombus get dislodge.
  • Short lasting obstruction.
  • Breakdown of embolus.
  • Reestablishment of perfusion.
  • Clearance of neurological deficit.

SYMPTOMS AND SIGNS

  • 5 risk factors are related with a higher 3 month risk of recurrent stroke
  1. Age >60 years.
  2. Symptom duration >10min.
  3. Weakness.
  4. Speech impairment.
  5. Diabetes mellitus.

  CAROTID TERRITORY.

  • Ipsilateral mono ocular blindness, contralateral hemiparesis, hemianesthesia, dysarthria, monoparesis, isolated facial weakness or sensory symptoms of face or limbs, reduced common carotid pulsation and bruit over carotid artery in neck, crystals of cholesterol in retinal vessels.

   VERTEBRO-BASILOR TERRITORY.

  • Ataxia, hemianopia, diplopia, sudden fall, weakness on both sides, difficulty in swallowing, vertigo and tinnitus are common.

INVESTIGATIONS

  • ROUTINE TEST FOR STROKE.
  1. Full blood count.
  2. E.S.R.
  3. Serological test for syphilis.
  4. Blood glucose, urea, proteins.
  5. Chest x ray.
  6. IN YOUNGER PATIENTS.
  1. Anti nuclear factor.
  2. Cholesterol
  3. Coagulation studies-anti thrombin |||,protein S and C.
  4. ADDITIONAL TESTS.
  5. IN VERTIBRO BASILAR TERRITORY.
  6. Lying and supine B.P.
  7. 24 hour E.C.G monitoring.
  8. X ray cervical spine.
  9. M.R.I angiography.

B.     IN CAROTID T.I.As

  1. C.T scan or M.R.I of  head.
  2. Carotid Doppler study.
  3. Arteriography.

EVALUATION OF RISK FACTOR.

  1. H.T.N
  2. D.M.
  3. Arterial disease affecting heart and limbs.
  4. Cardiac disease.
  5. Smoking.

TREATMENT

  1. General.
  2. Maintain airway and clear recreation, chest physiotherapy.
  3. Skin care by changing position to prevent bed sore.
  4. Nasogastric tube to maintain adequate hydration or to prevent vomiting.
  5. Bladder care by catheterization.

2.     SPECIFIC MEASURES.

  • Blood pressure :-rapid reduction in blood pressure may increase size of infarct, hence it is gradually reduced over days.
  • Anti edema measures: –
  • Mannitol 20% I.V over 20 min three or four times a day. 
  • Glycerol 30 ml orally three times a day.
  • Maintain blood sugar level.
  • Avoid raise in body temperature.
  • Avoid hypoxia.

    ANTICOAGULANTS.

  • Anticoagulants like heparin are indicated in following.
  • Recent myocardial infarction where they are used for 3 month.
  • Previous myocardial infarction with ventricular aneurysm.
  • Presence of artificial valve.
  • Progressive stroke.

     THROMBOLYTIC THERAPHY.

  • Recombinant tissue plasminogen activator is useful within first 3 hour in ischemic stroke in patient above 18 years.

    Contraindications

  1. Blood on C.T. SCAN.
  2. Active internal bleeding.
  3. Systolic pressure >185 mmHg, diastolic >110 mmHg.
  4. History of intra cranial bleeding.
  5. DOSE-0.9 mg /kg with 10% of total dose as bolus and rest over 1 hour.